The present invention relates to a novel chemical-sensitization resist composition or, more particularly, to a chemical-sensitization resist composition, which may be positive-working or negative-working, capable of giving a patterned resist layer having an excellently orthogonal cross sectional profile with high sensitivity and high pattern resolution.
It is a trend in recent years that the photolithographic patterning works in the manufacture of semiconductor devices, liquid crystal display panels and the like are conducted by using a chemical-sensitization resist composition. The working principle of the chemical-sensitization resist composition is that the solubility behavior of the resist layer in an alkaline developer solution is changed in the pattern-wise exposed areas by the catalytic activity of an acid generated from an acid-generating agent contained in the resist composition by the exposure to light. Chemical-sensitization resist compositions in general have an advantage of high sensitivity because good latent images can be formed even with a low exposure dose when the acid-generating agent has a high efficiency for radiation-induced generation of an acid.
Chemical-sensitization resist compositions are classified into positive-working and negative-working compositions, each of which comprises an acid-generating agent capable of releasing an acid by irradiation with actinic rays and a film-forming resinous ingredient which is subject to a change in the solubility in an aqueous alkaline solution by the interaction with an acid.
In the positive-working chemical-sensitization resist compositions, the film-forming resinous ingredient most widely under current use is a polyhydroxystyrene substituted for a part of the hydroxyl groups by acid-dissociable solubility-reducing groups such as tert-butoxycarbonyl groups, tetra-hydropyranyl groups and the like so as to be rendered insoluble in an aqueous alkaline solution. On the other hand, the negative-working chemical-sensitization resist compositions are formulated, as the film-forming resinous ingredient, with a combination of an alkali-soluble resin such as a novolak resin and polyhydroxystyrene resin optionally substituted for a part of the hydroxyl groups by the above mentioned solubility-reducing groups and an acid-crosslinkable compound such-as melamine resins, urea resins and the like.
It is known to employ an oximesulfonate compound as the acid-generating agent in a chemical-sensitization resist composition as is disclosed in Japanese Patent Kokai 1-124848, 2-154266, 2-161444 and 6-17433. The oximesulfonate compounds disclosed there include those having a cyano group in the molecule such as
.alpha.-(p-toluenesulfonyloxyimino)phenyl acetonitrile, PA1 .alpha.-(p-chlorobenzenesulfonyloxyimino)phenyl acetonitrile, PA1 .alpha.-(4-nitrobenzenesulfonyloxyimino)phenyl acetonitrile, PA1 .alpha.-(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino)phenyl acetonitrile, PA1 .alpha.-(benzenesulfonyloxyimino)-4-chlorophenyl acetonitrile, PA1 .alpha.-(benzenesulfonyloxyimino)-2,4-dichlorophenyl acetonitrile, PA1 .alpha.-(benzenesulfonyloxyimino)-2,6-dichlorophenyl acetonitrile, PA1 .alpha.-(benzenesulfonyloxyimino)-4-methoxyphenyl acetonitrile, PA1 .alpha.-(2-chlorobenzenesulfonyloxyimino)-4-methoxyphenyl acetonitrile, PA1 .alpha.-(benzenesulfonyloxyimino)-2-thienyl acetonitrile, PA1 .alpha.-(4-dodecylbenzenesulfonyloxyimino)phenyl acetonitrile, PA1 .alpha.-(4-toluenesulfonyloxyimino)-4-methoxyphenyl acetonitrile, PA1 .alpha.-(4-dodecylbenzenesulfonyloxyimino)-4-methoxyphenyl acetonitrile, PA1 .alpha.-(4-toluenesulfonyloxyimino)-3-thienyl acetonitrile, and the like. PA1 (A) 100 parts by weight of a film-forming resinous ingredient subject to changes in the solubility in an aqueous alkaline solution by interacting with an acid; and PA1 (B1) from 0.5 to 20 parts by weight of an acid-generating agent capable of releasing an acid by exposure to actinic rays, which is an oximesulfonate compound having a cyano group in the molecule represented by the general formula EQU R.sup.1 --C(CN).dbd.N--O--SO.sub.2 --R.sup.2, (I)
As is taught in Japanese Patent Kokai 2-154266, these oximesulfonate compounds having a cyano group in the molecule can release an acid by the energy of various kinds of actinic rays such as deep ultraviolet light, electron beams, ion beams, X-rays and the like and, when a positive-working chemical-sensitization resist composition comprising such an oximesulfonate compound and a film-forming resinous ingredient in combination is subjected to patterning by electron beam scanning, a patterned resist layer of about 0.35 .mu.m diameter in a hole pattern can be obtained. Also, a photocured patterned resist layer can be obtained from a negative-working chemical-sensitization resist composition comprising the oximesulfonate compound and a combination of a resin and an acid-crosslinkable compound by patterning with deep ultraviolet light.
In the manufacturing process of semiconductor devices in recent years with a rapidly proceeding trend toward a higher and higher degree of integration requiring ultrafine photolithographic patterning works, the above mentioned resist compositions are no longer quite satisfactory in several respects. Accordingly, a further improved chemical-sensitization resist composition capable of giving a patterned resist layer of an excellent cross sectional profile with a further improved pattern resolution and still with a high sensitivity is eagerly desired.